TC1223/TC1224

DS21368C-page 4

 2002-2012 Microchip Technology Inc.

3.0

DETAILED DESCRIPTION

The TC1223 and TC1224 are precision fixed output

voltage regulators. Unlike bipolar regulators, the

TC1223 and TC1224’s supply current does not

stable and within regulation over the entire 0mA to

consideration in RTC and CMOS RAM battery back-up

applications).

Figure 3-1 shows a typical application circuit. The

regulator is enabled any time the shutdown input

controlled by a CMOS logic gate, or I/O port of a micro-

controller. If the SHDN input is not required, it should be

connected directly to the input supply. While in

shutdown, supply current decreases to 0.05

A (typical)

FIGURE 3-1:

TYPICAL APPLICATION

CIRCUIT

3.1

Output Capacitor

A 1

F (min) capacitor from V

OUT

to ground is

recommended. The output capacitor should have an

effective series resistance greater than 0.1

 and less

than 5.0

, and a resonant frequency above 1MHz. A

1

F capacitor should be connected from V

there is more than 10 inches of wire between the

regulator and the AC filter capacitor, or if a battery is

used as the power source. Aluminum electrolytic or

tantalum capacitor types can be used. (Since many

aluminum electrolytic capacitors freeze at approxi-

mately -30°C, solid tantalums are recommended for

applications operating below -25°C.) When operating

from sources other than batteries, supply-noise

rejection and transient response can be improved by

increasing the value of the input and output capacitors

and employing passive filtering techniques.

TC1223

TC1224

SHDN

GND

NC

1

μF

+

Shutdown Control

(to CMOS Logic or Tie

1

μF

+

Battery

+